High compression piston ring and piston assembly

ABSTRACT

A piston and ring assembly for internal combustion engines wherein a piston mounts a split piston ring having a portion seated in a groove for the ring and a portion extending radially outwardly of the piston to engage the cylinder wall, the cylinder wall engaging portion projecting longitudinally outwardly beyond the piston end wall a distance such that the fuel explosion forces exert sufficient radial pressure on the longitudinally projecting portion to seal off explosion residuals which otherwise would leak past between the ring and cylinder wall.

United States Patent Sullivan Aug. 29, 1972 [54] HIGH COMPRESSION PISTONRING 3,363,608 1/ 1968 Scherenberg et al. ...92/ 171 X AND PISTONASSEMBLY FOREIGN PATENTS OR APPLICATIONS [72] Inventor: Edward F.Sullivan, 4465 Bradford S Saginaw, Mich 4 03 843,780 7/1952 Germany"..277/178 I 587,913 5/1947 Great Britain ..92/246 [221 P119511 May22,1970 719,537 12/1954 Great Britain ..92/245 [21] Appl. No.: 39,657

Primary Examiner-Edgar W. Geoghegan Assistant Examiner-Irwin C. Cohen[52] US. Cl. ..92/169, 92/181, 92/194', Attorneybemman & M c ll h92/246, 277/178 [51] Int. Cl .,.....F16j 9/02, F16j 9/08, F16j 11/04[57] ABSTRACT [58] Field of Search ..92/181,182,184,-185, 195, I

. 92,240, 241 246, 194; 277/178; 92/169 171 'A 1111811011 and ringassembly for lntemal combust on engmes wherein a plston mounts a splitp1ston rmg having a portion seated in a groove for the ring and a [56]References cued portion extending radially outwardly of the piston toUNITED STATES PATENTS engage the cylinder wall, the cylinder wallengaging portion proectin lon 'tudinally outwardly beyond 1,159,06611/1915 Moore ..92/246 the piston 1 walgl a disgtlance Such that thefuel PM 1,453,448 5/1923 Day ..92/246 Sion forces exert Sufficientradial pressure on the 10m 1,616,310 2/1927 Peltene ..92/246 g nyprojecting portion to Seal off explosion 1,737,056 1 1/ 1929 Mueller..92/246 X residuals which otherwise would leak p between h 1,784,50512/ 1930 Teetor ..92/246 X ring and cylinder walL 1,956,355 4/ 1934Junkers ..92/246 2,325,556 7/1943 Taylor, Jr. et a1. ..92/241 7 Claims,3 Drawing Figures Patented Aug. 29, 1972 H 3,687,018

5 ll \lllllll HF" 1 v R .4 6 II C IO P FIGI INVENTOR EDWARD F. SULLIVANFIG. 2 L manMccullocfi ATTORNEYS HIGH COMPRESSION PISTON RING AND PISTONASSEMBLY This invention relates to piston rings and more particularly toa novel piston ring and piston assembly which is more efficient thanprior art constructions. Presently smog and air pollution are matters ofconsiderable concern in our highly populated cities and these problemsare, in large part, due to the emission of incompletely combusted fuelgases from motor vehicles. This is believed due in considerable part topiston ring wear. For example, in a new vehicle the so-called blow-by ofexplosion gases in the cylinders of the engines is something on theorder of to 3 percent. After the vehicle has traveled 25,000 miles, theblow-by is closer to 50 percent, and after 50,000 miles it may be in theneighborhood of as much as 80 percent if the rings have not beenreplaced. This blow-by of gases between the rings and cylinders from thehead end of the pistons rearwardly, is then emitted to atmosphere as acontaminant.

One of the objects of the present invention is to provide a compressionring for the head end of the piston which includes a cylinder engagingportion which extends longitudinally forwardly of the piston andprovides sufficient longitudinally projecting surface that explosionforces expand the ring radially to drastically reduce the blowby ofgases, even after considerable wear of the rings.

A further object of the invention is to provide a compression ring andpiston assembly of economic and efficient construction which does notrequire re-design of the piston cylinder or cylinder head.

Other objects and advantages of the present invention will becomeapparent to those of ordinary skill in the art by the followingdescription when considered in relation to the accompanying drawings inwhich:

FIG. 1 is a sectional elevational view of a typical compression ring andpiston assembly fabricated according to the invention;

FIG. 2 is a transverse sectional view taken on the line 22ofFIG.1;and

FIG. 3 is an enlarged view, similar to FIG. 1, showing a slightlymodified construction.

Referring now more particularly to the accompanying drawings, whereinonly preferred embodiments of the invention are shown, and in the firstinstance particularly to FIGS. 1 and 2 wherein the simplest form of theinvention is illustrated, a letter B generally refers to the engineblock of a conventional internal combustion engine which includes anumber of cylinders generally indicated C, having cylindrical interiorwalls which may be provided by a liner as in FIGS. 1 and 2, or simply bya cylinder bore as in FIG. 3. Provided in each of the cylinders C toreciprocate therein is a piston, generally designated P, having, asusual, a compression ring groove 1 1 in its head end for seating acompression piston ring generally designated R. The cylinder head forthe engine block and cylinder is schematically depicted at H and, asshown, the liner forming the cylinder surface 10 projects slightly upinto the disc shaped recess 12 provided in the head H.

In all the views the piston P is shown in its forwardmost position andit is to be understood that the space 13 provided forwardly of thepiston P provides the explosion chamber into which the fuel gases to beexploded are compressed. As is well known, a spark provided by aconventional spark plug ignites the compressed, gasoline vapor in thespace 13 in an engine such as a conventional automobile engine and theexplosion forces drive the piston P sharply rearwardly. With all thepiston P in the engine cylinders connected by connecting rods, notshown, to the usual crankshaft, not shown, power is transmitted in theusual manner.

Each of the piston rings R, which are generally L- shaped orangle-shaped in cross section, include a radially inwardly projectingseating portion 14 which is shaped to fit the contour of the annulargroove 11, and a longitudinally or axially projecting wall portion 15whose peripheral surface is in close engagement with the cylinder wallsurface 10.

The ring R is, or course, a split ring, and about a ten thousandths inchclearance is maintained at the gap G. The operating clearance providedbetween the periphery of wall 15 and the cylinder wall surface 10 is, inhigh compression engines of this character, maintained at about fivethousandths of an inch. Thus, the piston P will be able to move back andforth in its cylinder 10 without undue wear and the ring R will, at thesame time, be able to move in a rotary direction in the groove 11, thislatter movement preventing deposit of carbons which would freeze thepiston ring R in position and lead to the rapid wear and destruction ofthe ring as an operating element.

-It is to be observed that the wall 15 projects a distance x past theradial end wall 16 of the piston P, the distance x being slightlygreater than the portion which does not project beyond the end wall 16.In operation, when an explosion of fuel gases occurs in chamber 13, theforces created by the explosion force the ring R radially in the mannerindicated by the arrows y and substantially prevent any tendency for thegaseous products of explosion to pass rearwardly between the ring R andwall 10 and eventually find their way to atmosphere. This prevention ofblow-by is accomplished even after the rings R have had considerable useand there has been considerable wear, such that the operating clearancebetween the periphery of ring R and cylinder wall 10 has considerablyincreased.

In FIG. 3, wherein a modified and improved preferred form of theinvention is disclosed as indicated and identical numerals are used todesignate similar parts, an annular groove 17a is shown in the inner orrear portion of the ring R to accommodate an annular coil spring 17,which, in the position shown, is stretched, and which exerts radiallyconstrictive forces tending to close the split ring R. At the same time,the wall 15 is reduced by an annular groove 18 to provide a reducedthickness wall section 18a which extends beyond the end of piston 16. Inoperation, when explosion gases force the wall 15 radially, the portion18a has a limited flexibility and the spring 17 tends to hold the rearportion of the ring R inwardly while letting the forward portion thereofradially expand to positively seal the cylinder 10 and prevent theblow-by of residual gases.

It should be understood that the outer peripheral surfaces of the ringsR utilized may be chromium plated or sprayed with a molybdenumpreparation, if desired.

It is further to be understood that the drawings and descriptive matterare in all cases to be interpreted as merely illustrative of theprinciples of the invention, rather than as limiting the same in anyway, since it is contemplated that various changes may be made invarious elements to achieve like results without departing from thespirit of the invention or the scope of the appended claims.

What is claimed is:

1. A piston and cylinder assembly comprising: engine cylinder meansproviding a piston-receiving cylinder wall and an explosion chamber; acylindrical piston axially reciprocable in said cylinder means andhaving an end wall portion facing said explosion chamber, said pistonhaving an annular groove in its periphery axially inward of said endwall portion; and a piston ring means having a portion seated in saidgroove, and a longitudinally projecting cylinder wall engaging portionextending axially outwardly beyond said piston end wall portion andexposed to the explosion gases over a distance such that the explosionin said chamber exerts sufficient radial pressure thereon tosubstantially seal off explosion residuals which otherwise would passbetween the ring means and cylinder wall, said ring, including theportion projecting longitudinally outwardly beyond said piston end wallportion having an external circumferential groove providing an axiallyextending, radially outwardly flexing wall, between axially inner andouter cylinder wall engaging land portions, and the axially outersurface of said inner land portion lying between the axially innersurface of the piston groove and the axially outer surface of saidpiston end wall portion. i

2. The structure defined in claim 1 wherein the axially inner landportion is substantially radially opposite the groove in the pistonaxially inward of said piston end wall portion.

3. The combination defined in claim 2 wherein the land portions andgroove have axially inner and outer, generally radial walls, and theouter radial wall of the axially inner land portion is spaced inwardfrom the axially outer radial wall of said piston groove.

4. A piston and cylinder assembly for fuel burning engines comprising:engine cylinder means providing a piston-receiving cylinder wall and anexplosion chamber; a cylindrical piston axially reciprocable in saidcylinder means and having an end wall facing said explosion chamber,said piston having an annular groove adjacent said end wall; and a splitpiston ring having a'portion seated in said groove, and a longitudinallyprojecting radially exposed, cylinder wall engaging portion extendingaxially outwardly beyond said piston end wall a distance such that theexplosion in said chamber exerts sufficient radial pressure thereon tosubstantially seal off explosion residuals which otherwise would passbetween the ring andcylinder wall, said ring, including the portionextending longitudinally outwardly beyond said piston end wall, havingan external circumferential groove around its entire periphery toprovide an axially extending, radially outwardly flexing wall betweenaxially inner and outer cylinder wall engaging land portions, and saidexternal circumferential groove extending axially from a point oppositesaid annular groove in the piston to a point axially beyond said pistonend wall.

5. The combination defined in claim 4 in which said cylinder meansincludes a cylinder bore having a liner 3. iil fiilliililigila llle'iiill gfiirfi l in which said groove has parallel radial side walls andthe ring portion seated therein is rectangular in cross section and issnugly, but movably, received therein.

7. The combination defined in claim 4 in which an exteriorcircumferential groove is provided in said inner wall engaging land ofsaid ring adjacent the seating portion thereof; and a constrictingannular spring is received therein and exerts a radially compressingforce on said ring.

1. A piston and cylinder assembly comprising: engine cylinder meansproviding a piston-receiving cylinder wall and an explosion chamber; acylindrical piston axially reciprocable in said cylinder means andhaving an end wall portion facing said explosion chamber, said pistonhaving an annular groove in its periphery axially inward of said endwall portion; and a piston ring means having a portion seated in saidgroove, and a longitudinally projecting cylinder wall engaging portionextending axially outwardly beyond said piston end wall portion andexposed to the explosion gases over a distance such that the explosionin said chamber exerts sufficient radial pressure thereon tosubstantially seal off explosion residuals which otherwise would passbetween the ring means and cylinder wall, said ring, including theportion projecting longitudinally outwardly beyond said piston end wallportion having an external circumferential groove providing an axiallyextending, radially outwardly flexing wall, between axially inner andouter cylinder wall engaging land portions, and the axially outersurface of said inner land portion lying between the axially innersurface of the piston groove and the axially outer surface of saidpiston end wall portion.
 2. The structure defined in claim 1 wherein theaxially inner land portion is substantially radially opposite the groovein the piston axially inward of said piston end wall portion.
 3. Thecombination defined in claim 2 wherein the land portions and groove haveaxially inner and outer, generally radial walls, and the outer radialwall of the axially inner land portion is spaced inward from the axiallyouter radial wall of said piston groove.
 4. A piston and cylinderassembly for fuel burning engines comprising: engine cylinder meansproviding a piston-receiving cylinder wall and an explosion chamber; acylindrical piston axially reciprocable in said cylinder means andhaving an end wall facing said explosion chamber, said piston having anannular groove adjacent said end wall; and a split piston ring having aportion seated in said groove, and a longitudinally projecting radiallyexposed, cylinder wall engaging portion extending axially outwardlybeyond said piston end wall a distance such that the explosion in saidchamber exerts sufficient radial pressure thereon to substantially sealoff explosion residuals which otherwise would pass between the ring andcylinder wall, said ring, including the portion extending longitudinallyoutwardly beyond said piston end wall, having an externalcircumferential groove around its entire periphery to provide an axiallyextending, radially outwardly flexing wall between axially inner andouter cylinder wall engaging land portions, and said externalcircumferential groove extending axially from a point opposite saidannular groove in the piston to a point axially beyond said piston endwall.
 5. The combination defined in claim 4 in which said cylinder meansincludes a cylinder bore having a liner sleeve therein providing saidcylinder wall.
 6. The combination defined in claim 4 in which saidgroove has parallel radial side walls and the ring portion seatedtherein is rectangular in cross section and is snugly, but movably,received therein.
 7. The combination defined in claim 4 in which anexterior circumferential groove is provided in said inner wall engagingland of said ring adjacent the seating portion thereof; and aconstricting annular spring is received therein And exerts a radiallycompressing force on said ring.